Electromagnetic Parking Lock Actuator With Coaxial Latching

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Solution Overview

Problem

Conventional parking lock actuations in electric vehicles require expensive electric actuator drives, large installation space, and complex control systems, including DC motors, spindle mechanisms, and position monitoring, which increase costs and reduce efficiency.

Innovation Solution

A parking lock system utilizing an electromechanical actuator with a magnetic coil and spring-loaded pressure plates, allowing for simple current supply in one direction to achieve safe retraction and extension, eliminating the need for spindle mechanics and position monitoring, and reducing installation space through coaxial arrangement of latching and adjustment mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electric actuator drives with DC motors and spindle mechanisms are used, then reliable actuation is achieved, but device complexity and installation space increase

Engineering Contradiction:
Improveactuation reliabilityVSAvoidactuator complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the conventional electric actuator drive (DC motor, spindle mechanism) with a simple electromagnetic actuator consisting of a magnetic coil and armature. This substitution eliminates complex mechanical components while maintaining actuation functionality through direct electromagnetic force generation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and eliminates unnecessary components from the conventional actuator system, removing the DC motor, spindle mechanism, position monitoring systems, and complex control units, retaining only the essential electromagnetic actuation elements needed for parking lock operation.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If conventional electric actuator drives are used, then actuation function is achieved, but installation space increases

Engineering Contradiction:
Improveactuation functionVSAvoidinstallation space
Core Design Contradiction:
Ease of operationVSArea of stationary object

Solution Approach 1:

The patent employs a nested arrangement where the electromagnetic actuator components (magnetic coil, armature, pressure plates) are concentrically arranged around a common axis. The locking mechanism and adjustment mechanism are arranged coaxially, with the adjustment mechanism positioned within the locking mechanism's radial space, maximizing space utilization.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from a conventional linear actuator layout to a radial/concentric arrangement, utilizing the radial dimension around the parking lock's central axis. This dimensional reorganization allows components to be arranged in a compact circular pattern rather than requiring linear space.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If conventional electric actuator drives with position monitoring are used, then precise control is achieved, but cost increases

Engineering Contradiction:
Improveposition controlVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements a self-servicing system where the spring-loaded pressure plates automatically return the locking mechanism to its initial position after actuation. The mechanical spring return mechanism eliminates the need for position sensors, feedback systems, or complex control algorithms to manage the actuator's movement cycles.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent employs periodic actuation where the magnetic coil is energized only during the actuation phase, and the spring automatically returns the mechanism during the return phase. This periodic on-demand actuation eliminates continuous control requirements and associated monitoring systems.

Inventive Principle:
Principle #19Periodic action

4Device complexity

If spring-loaded pressure plates are used for automatic return, then device complexity is reduced, but force control precision may worsen

Engineering Contradiction:
Improvemechanism complexityVSAvoidreturn force control
Core Design Contradiction:
Device complexityVSForce

Solution Approach 1:

The patent utilizes spring preloading to establish a predetermined return force parameter. By designing the spring with specific stiffness and preload characteristics, the system achieves reliable automatic return without requiring active force control systems, sensors, or complex regulation mechanisms.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution provides a cost-effective, compact, and reliable parking lock system with reduced part complexity, enabling high holding forces and fast actuation, while eliminating the need for complex control systems and position monitoring, and allowing for easy emergency unlocking.

Implementation Method 1

an electromechanical actuator (10) comprising a magnetic coil (12) and an armature (14) actuated by it

Methodology Applied
Scientific EffectElectromagnetic actuation: Electromagnet

Implementation Method 2

The armature (14) is acted upon by a tension spring (16)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

The compression spring (44) is supported against a counter bearing (46)

Methodology Applied
Scientific EffectElasticity: Spring

Data Source

PatentEP3879138B1Park locking system
Publication Date: 2023.11.29 ROBERT BOSCH GMBH
  • EP3879138B1 patent drawingFigure 1
  • EP3879138B1 patent drawingFigure 2
  • EP3879138B1 patent drawingFigure 3

AI summary

The invention relates to an electromechanical actuator (10) of a parking lock system with a ratchet wheel (84) and a locking pawl (86) of a vehicle. The electromechanical actuator (10) comprises a magnetic coil (12) and an armature (14) actuated by it. When the magnetic coil (12) is energized (52), it moves an adjusting mechanism (20) translationally, which in turn moves a spring-loaded detent mechanism (26) translationally and rotationally, thereby locking a bolt (42) either in its retracted position (80) or in its extended position (82).